1. Summary of the Invention
The present invention is directed to an apparatus for inspecting articles using a fan-shaped radiation beam, and in particular to such an apparatus suitable for examining containers and/or vehicles at an airport to determine whether the containers and/or vehicles contain explosives, weapons, drugs, smuggled goods or the like.
2. Description of the Prior Art
An apparatus for examining containers to determine the presence of illegal articles is disclosed in German Utility Model 8506187, corresponding to U.S. Pat. No. 4,722,096. In this apparatus, the fan plane of a radiation generator is aligned perpendicularly to a conveying path for the containers. After passing through a partial cross-section of the container, the fan-shaped radiation beam is incident on a L-shaped line radiation detector, to which a means for signal evaluation is connected. For complete transillumination of the entire cross-section of the container, the radiation generator is pivoted through the fan angle, or alternatively three separate radiation generators may be used which generate respective fan-shaped radiation beams offset by the fan angle, so that the radiation from each fan beam is incident on a different region of the L-shaped radiation detector. The signals from the radiation detectors are processed in an image processing system while the container is being conducted past the radiation generator and the radiation detector on a conveying path formed by rollers. A radiation silhouette of the container is reproduced on a monitor.